For many years, the textile industry has sought ways for producing yarns from continuous filaments such that the yarns have the characteristics of a spun yarn comprised of staple. Prior to the advent of synthetic filaments, all yarns were produced from staple products. Synthetic filaments, however, are made as continuous filaments and, in order to provide the desirable effects of staple products, a vast proportion of synthetic filament production is cut into staple length fibers. Such fibers are then twisted into yarns, called spun yarns.
Spun yarns have a particularly desirable characteristic of being somewhat fuzzy or hairy along their length giving them the desirable attributes of softness and cover and, when produced into fabrics, the ability to produce low density, porous, permeable and comfortable materials. Continuous filament yarns also have many desirable attributes but they also have their limitations, particularly in respect to bulk, cover and comfort factors. Nevertheless, continuous filament yarns have replaced spun yarns in many end uses. Of course, it is obvious that if a continuous filament yarn could be made into a spun-like yarn, the otherwise expensive steps of cutting continuous fibers into staple followed by carding, coning and twisting into roving, followed by drafting and twisting further into yarns could be eliminated.
Many attempts have been made to accomplish this feat but various limitations in the resulting product have kept such continuous filament yarns from being complete replacements for spun yarns. In particular, previous methods, such as the very popular false twist texturing method for crimping continuous filament yarns to produce bulk and cover, have had their limitation in that the yarns always end up having a rather synthetic feel and look. This is probably due to the lack of the fuzzy and hairy projections which are present in spun yarns.
Another attribute staple yarns have is the ability to blend different fibers of different dyeability, such as polyester and wool or polyester and cotton, to produce a heather effect when dyed. Many suggestions have been made for combining filament yarns but such previous attempts have failed to effect an adequate blending of the fibers such that the yarns would equal the appearance of staple in fabric form. The lack of a total intimate blending results in an undesirable moire or plaiting appearance in the resulting fabric.
An additional problem is also encountered in producing ingrain filament yarns. The best blending was previously accomplished by combining the different yarns prior to drawing and then drawing the yarns as a single combined yarn. Different yarns, however, require different drawing tensions or ratios such that the best dyeing results would in turn require a matching of the ultimate drawing tension. This in turn would require different spinning conditions such that the drawing tensions could be matched and therefore the two yarns could not be co-spun for optimum results. The present method minimizes or negates the critically of matched drawing tensions in the draw texturing step.
It is an object of the present invention to produce a simulated spun-like ingrain yarn which is made from continuous filaments and does not have the disadvantages of the prior art.
It is another object of the present invention to produce a spun-like ingrain yarn which has high knitting and weaving efficiencies.
It is yet another object of the present invention to provide a spun-like ingrain yarn which has substantially different characteristics from previous bulked yarns while at the same time having the desirable characteristics of staple blend spun yarns.
It is a further object of the present invention to provide an ingrain filament yarn which, in fabric form, dyes to a fine grain heather appearance.
These and other objects of the present invention will become apparent to those skilled in the art from a reading of the present description.